A charged particle beam apparatus, e.g., an electron microscope typified by a transmission electron microscope (Transmission Electron Microscope, TEM) adopts a side-entry sample stage into which a sample holder is introduced in a traverse direction relative to a mirror body.
PTL 1 relates to a side-entry sample stage. PTL 1 describes a structure including: a slider tube that slides in a longitudinal direction of the sample holder and can move together with the sample holder; a touching member that contacts the slider tube and determines an setting position of the sample holder; and an elastic body arranged between the slider tube and the touching member. The structure is for reducing sample drift due to distortion of an O-ring that seals between a vacuum sample chamber and the atmosphere in a sample holder.